Housing case for a rotary piston internal combustion engine



Jan. 27, 1970 wOLF-DIETER BENSINGE'R 3,491,727

HOUSING CASE FOR A ROTARY PISTON INTERNAL COMBUSTION ENGINE 2Sheets-Sheet 1 Filed Feb. 5. 1967 INVENTOR WOLF DIETER BENSINGER i is QATTORNEYS Jan. 27, 1970 WOLF-DIETER BENSINGER 3,491,727

HOUSING CASE FOR A RGTARY PISTON INTERNAL COMBUSTION ENGINE 2Sheets-Sheet 2 Filed Feb. 3, 1967 I N VEN TOR. WOL F DIE TE EE/VSI/VGERUnited States Patent M Int. Cl. F02b 53/14, 53/00 US. Cl. 1238 8 ClaimsABSTRACT OF THE DISCLOSURE A housing for a rotary piston internalcombustion engine, especially of trochoidal construction, whichcomprises a housing case provided internally with running surfaces alongwhich slide the piston corners, and lateral housing parts closing offthe housing case in the axial direction of the engine, whereby a smallgroove extending substantially parallel to the running surfaces isprovided in the sidewall of each housing case closely adjacent to therunning surfaces. The small groove may extend over the entirecircumference of the housing case or only over that portion which isconsiderably hotter than the rest of the housing case.

Background of the invention The present invention relates to a housingcase for a rotary piston internal combustion engine, especially for aninternal combustion engine of trochoidal construction, which housingcase is provided with an internal running surface for the piston and tothe lateral side walls of which are secured lateral housing parts onboth sides in the axial direction.

It has been noted with rotary piston internal combustion engines oftrochoidal construction that the lateral housing parts deform becausethe housing case, which becomes very much hotter within the area of thecompression chamber and of the expansion chamber than within the area ofthe suction chamber, expands unevenly and is distorted thereby. Thegreatest distortion and warping thereby occurs in the area of therunning surface for the piston. The consequence thereof is a distortionof the lateral housing parts which should remain completely flat in theinterest of a good oil seal.

Summary of the invention The present invention is concerned with the aimto so construct the housing case that a non-uniform expansion thereof inproximity of the running surface cannot affect the lateral parts of theinternal combustion engine housing. The underlying problem is solved ina simple manner according to the present invention in that a groove isprovided in each lateral wall of the housing case closely adjacent therunning surface and extending parallel thereto at least over a part orover the entire circumference.

By the arrangement of at least one groove, the edge of the hOusing casecan deform within the area of the running surface during heating upwithout exerting a pressure on the lateral housing parts which mightdeform the same.

In an advantageous construction of the inventive concept the groove maybe arranged exclusively within the hot arc of the housing case, forexample, within the area between the spark plug and the exhaust channel.

Accordingly, it is an object of the present invention to provide ahousing for a rotary piston internal combustion engine, especially oftrochoidal construction, which is simple in construction, yet eliminatesthe afore- 3,491,727 Patented Jan. 27,- 1970 mentioned drawbacksencountered with the prior art constructions in an effective manner.

Another object of the present invention resides in a housing case forrotary piston internal combustion engines which greatly improves the oilsealing properties thereof under all operating conditions.

A further object of the present invention resides in a housing for arotary piston internal combustion engine of trochoidal constructionwhich effectively prevents deformation and distortions of the lateralhousing parts which might adversely affect the tightness of the oilseals.

These and further objects, features and advantages of the presentinvention will become more obvious from the following description whentaken in connection with the accompanying drawing which shows, forpurposes of illustration only, one embodiment in accordance with thepresent invention, and wherein:

FIGURE 1 is an elevational view in the axial direction on the housingcase of rotary piston internal combustion engine of trochoidalconstruction, according to the present invention;

FIGURE 2 is a cross-sectional view through the housing case, taken alongline lI-II of FIGURE 1, with the lateral housing parts attached; and

FIGURE 3 is an elevational view, similar to FIGURE 1, on a modifiedembodiment of a housing case in accordance with the present invention.

FIGURES 4 and 5 are similar to FIGURES 1 and 2, respectively, showingtwo grooves.

Referring now to the drawing wherein like reference numerals are usedthroughout the various views to designate like parts, the housing of arotary piston internal combustion engine of trochoidal constructionaccording to FIGURES 1 and 2 is essentially constituted by the housingcase 1 and by the two lateral housing parts 2 which are attached to thehousing case 1 in the axial direction. The housing case 1 is equippedwith a running surface 3 along which slides the piston of the internalcombustion engine during its rotation. In the interest of a safe oilsealing between the end walls of the piston and the lateral housingwalls 4 or the lateral housing parts 2, it is necessary that the lateralwalls 4 remain completely fiat. Hence, no distortion should occur whichmight be caused by the fact that the housing case 1 heats up inproximity to its running surface 3 by the operation of the internalcombustion engine and presses against the side walls 4 of the lateralhousing parts 2. For purposes of avoiding the distortion of the lateralwalls 4, a groove 7 of rectangular cross section is provided in eachside wall 5 of the housing case 1 at a peripherally small distance 6 tothe running surface 3. Between each groove 7 and the running surface 3by the lateral walls 5 of the housing case 1 a rim or edge is formedwhich cannot transmit any large forces. This rim or edge 8 is deformedif the housing case 1 expands within the area of its running surface 3in the axial direction so that no pressure is exerted on the lateralwalls 4 of the lateral housing parts 2.

According to FIGURE 3, it suflices if the grooves 7 in the lateral walls5 of the housing case I extend only within the area of the so-called hotare 9 between a spark plug 10 and the outlet channel 11.

While I have shown and described two embodiments in accordance with thepresent invention, it is understood that the same is not limited theretobut is susceptible of numerous changes and modifications as known to aperson skilled in the art. For example, in lieu of a single groove ineach side wall of the housing case, two grooves, as shown in FIGURES 4and 5, may possibly be provided in each wall of the case which arearranged parallel to each other and at a small distance from each other.

Thus, it is obvious that the present invention is not limited to thedetails shown and described herein and I therefore do not wish to belimited thereto but intend to cover all such changes and modificationsas are encompassed by the scope of the appended claims.

I claim:

1. A housing case for a rotary piston internal combustion engine,especially of trochoidal construction which includes running surfacemeans for the piston on the inside thereof, and to the lateral walls ofwhich are attached on both sides in the axial direction lateral housingparts, wherein the improvement comprises anti-warp groove means providedin each lateral wall of the housing case closely adjacent the runningsurface means and approximately parallel thereto, said grove means beingspaced so closely adjacent to the running surface means that edgeportions are formed in the housing case incapable of transmitting largeforces but capable of deformation in case of thermal expansion so as toprevent distortion and warping in the lateral walls.

2. A housing case according to claim 1, wherein the groove means extendat least partly over the circumference of the running surface means.

3. A housing case according to claim 1, wherein the groove means extendover the entire circumference of the running surface means.

4. A housing case according to claim 1, wherein the groove means isarranged exclusively within the area of the hot arc of the housing case.

5. A housing case according to claim 4, wherein said hot arc is locatedbetween the spark plug and the outlet channel.

6. A housing case according to claim 1, wherein two groove means areprovided in each lateral wall which extend substantially parallel toeach other.

7. A housing case according to claim 3, wherein two groove means areprovided in each lateral wall which extend substantially parallel toeach other.

8. A housing case according to claim 4, wherein two groove means areprovided in each lateral wall which extend substantially parallel toeach other.

References Cited UNITED STATES PATENTS 5/1963 Paschke 230-145 7/1966Gassmann.

